Over the last few years, progress has been achieved in developing liquids for conserving corneas that have been taken for use as grafts. At present, the disk comprising the cornea surrounded by a scleral ring having a width of one or two millimeters is put in a conservation liquid and can be used a few days later.
The graft proper is cut to shape by means of an assembly known as an artificial chamber which holds the cornea by clamping it via the scleral ring and which has means for supporting a cutting tool known as a keratome. Two types of keratome are available: a bore or a plane, depending on whether the operator desires to make a perforating cut (i.e. through the entire thickness of the cornea), or on the contrary a lamellar cut comprising a determined thickness of the cornea. The artificial chamber serves to stiffen the cornea by pressurizing it using physiological serum or air, thus making it possible to perform cutting via the front face (epithelium) under conditions that are very close to those that exist when removing diseased cornea that needs to be replaced.
Various structures have already been proposed for artificial chambers. In particular, French patent No. 2 712 184 discloses an artificial chamber comprising a stand, a cornea support carried by the stand, having a vertical axis and possessing a head with a supporting top face into which there opens up at least one feed orifice, and a clamping ring that is movable in translation relative to the cornea support along the axis thereof between a clamping position in which its top face clamps the corneo-scleral disk against the clamping ring, and a release position in which its top face is at a distance from the clamping ring.